Fiber-tip writing pen with replaceable cartridge



May 27, 1969 R. J. BURNHAM FIBER-TIP WRITING PEN WITH REPLACEABLE CARTRIDGE Filed OC'C. 21. 1966 United States Patent O U.S. Cl. 401-199 7 Claims ABSTRACT F THE DISCLOSURE A fiber-tip writing pen with a replaceable cartridge. The cartridge has a planar flange between its ends. The cartridge has a male thread immediately in front of the flange. A male threaded plug extends from the rear of the cartridge. A barrel ensheaths the cartridge from the flange rearwardly and is held in place by a tapped ferrule which engages the thread on the plug and presses the barrel against one longitudinally facing surface of the flange. A cap is adapted to be screwed on to the cartridge thread and covers the front of the cartridge. The diameters of the cap, the llange, the barrel and the ferrule present a substantially unbroken surface from front to back of the pen when the cap is in place.

The present invention relates to a liber-tip Writing pen with a replaceable ink-carrying cartridge. Such a pen may be used both for marking and writing It is the primary object of the present invention to provide a new and improved fiber-tip wrriting pen having a replaceable ink-carrying cartridge, that is, a cartridge which can be removed by the user from the pen when the cartridge is exhausted of its ink supply and replaced by a fresh cartridge with a full ink supply.

It is a further object of my invention to provide a replaceable cartridge for a fiber-tip writing pen of the character described, wherein the cartridge is adapted to be used with various differently shaped and colored ensheathing barrels, the interior configuration and the length of each such barrel being dictated by the requirements of the replaceable cartridge but the external shape, form and color of the barrel being the determination of the pen manufacturer.

It is still a further object of my invention to provide a replaceable cartridge for a fiber-tip writing pen of the character described wherein the cartridge, even while the pen has a trim look, has an exceptionally large ink carrying capacity so that the pen may be used for a large quantity of writing before the cartridge must be replaced.

It is yet another object of my invention to provide a liber-tip writing pen with a replaceable cartridge of the character described wherein a substantial surface portion of the cartridge forms a part of the external surface of the pen.

It is another object of my invention to provide a libertip writing pen with a replaceable cartridge of the character described wherein the pen is few in its number of parts, suitable for manufacture by mass production techniques, durable in wear, eflicient in use and economical in cost.

It is still another object of my invention to provide a fiber-tip writing pen with a replaceable cartridge of the character described wherein the cap of the pen has in one piece therewith an annular resilient sealing flange which circumferentially mates with and is urged radially inwardly against the forward portion of the cartridge, the aforesaid sealing preventing evaporation of the ink carried by the pen through the nib of the pen and the air vent.

It is still another object of my invention to provide a liber-tip writing pen with a replaceable cartridge of the lCe character described wherein the cartridge after incorporation into the pen has a colored portion which is visible to a user of the pen, the color of said portion identifying the color of the ink within the pen, independently of the barrel carried by the pen.

It is a further object of my invention to provide a liber-tip writing pen with a replaceable cartridge of the character described wherein the cartridge has indicia printed thereon and wherein the barrel is transparent so that the indicia on the cartridge is viewable by a user through the barrel.

Other objects of my invention in part will be obvious and in part will be pointed out hereinafter.

My invention accordingly consists in the features of the construction, combination of elements and arrangements of parts which will be exemplified in the fiber-tip writing pen hereinafter described and of which the scope of application will be indicated in the appended claims.

In the accompanying drawings in which is shown one possible embodiment of my invention:

FIG. 1 is a perspective view of my liber-tip writing pen with a replaceable ink-carrying cartridge;

FIG. 2 is a fragmentary enlarged axial cross-sectional view of the pen and taken substantially along the line 2--2 of FIG. 1; and

FIGS. 3 and 4 are enlarged radial cross-sectional views taken substantially along the lines, respectively, 3-3 and 4-4 of FIG. 2.

In accordance with the teaching of the present invention, there is provided a liber-tip writing pen having a replaceable ink-carrying cartridge. The cartridge, as is usual, has an internal chamber lled by ink absorbing material. The material is saturated with ink. A nylon or other type fiber nib protrudes from the forward end of the cartridge and the nib passes internally of the cartridge into contact with the ink absorbing material.

The cartridge is characterized by three elements: viz., a radially outwardly protruding annular circular llange located between the ends of the cartridge, a male screw thread on the cartridge forward of the flange and another male screw thread at the rear of the cartridge.

The liber-tip writing pen further includes a hollow tubular barrel which is telescoped over the cartridge. The barrel slides over the cartridge from the cartridges rear end. The barrel at its forward edge abuts the flange and at least at this point the barrel and the flange are of like outside diameters so that these two parts blend smoothly into one another. The rear edges of the barrel terminates adjacent the male screw thread formed on the rear of the cartridge. A hollow ferrule removably threads over the rear male screw thread and completes the rear end of the pen. The ferrule threads onto said screw thread to a point at which it abuts the rear edge of the barrel. Thus, the barrel is abutted on one end by the flange and on the other end by the ferrule. The ferrule and'the rear end of the barrel are also of like external diameters so that these parts blend smoothly into one another. A cap fits over the front of the pen and threadingly mates with the male screw thread in front of the flange. The cap has formed in one piece therewith an internal rearwardly protruding resilient annular flange which seats against a circumferential zone on the surface of the front portion of the cartridge rearwardly of the usual air vent. The flange is llexed radially outwardly when the cap is telescoped over the cartridge, the pres- 'sure of the ange against the cartridge engendering a good air seal between the cap and the cartridge, and preventing evaporation of ink from the cartridge through the nib and the air vent.

When the pen is in use, that is, has its cap removed, the flange as well as the portion of the cartridge in front of the flange is exposed and may be grasped by the lingers of the user. By making a surface portion of the cartridge a portion of the external surface of the pen, it is possible to make the interior chamber of the cartridge comparatively large without increasing the overall diameter of the liber-tip pen. The flange remains exposed and is part of the outside surface of the pen, even when the cover is on the pen; however, the portion of the cartridge in front of the ange is covered by the pen cap.

The cartridge may be replaced by simply unscrewing the ferrule from the rear of the cartridge, slipping the barrel olf of the rear of the cartridge, and then placing the barrel over a fresh cartridge and screwing the ferrule on its rear end. This replacement may be carried out quickly and easily by any user. Thus, since several manufacturers may use my cartridge as the core for their pens, and since one manufacturer may use the same cartridge for many pen styles, the cartridge will become a standard original equipment item as well as a standard replacement item.

Referring now in detail to the drawings, the reference numeral denotes a fiber-tip writing pen constructed in accordance with my invention. The pen includes a replaceable ink-carrying cartridge 12 which is elongated along a central axis. The cartridge includes a hollow double open-ended thin-walled plastic, e.g., polystyrene, tube 14. the tube having a constant internal diameter except at its forward portion Where the said internal diameter is reduced. The tube 14 delines an internal reservoir or chamber 16 which is elongated and which, due to the construction of the present pen, is of especially large inkbearing capacity. The rearward portion 14a of the tube is of rearwardly tapering diameter.

The tube 14 further includes in one-piece therewith a circular annular radially outwardly extending squat flange 18, said flange being located between the ends of the tube and desirably forward of the center of the cartridge. The ange is of constant width and has an external diameter larger than the external diameter of the remainder of the tube but only a fraction of an inch, c g., three-sixteenths of an inch, more than the external diameter of the rear portion 14a of the tube. The tiange lies in a plane perpendicular to the central axis of the tube.

The tube further includes in one-piece therewith an external, i.e., male, screw thread situated on the tube forwardly of the ange 18 with the rearwardmost turn of the screw thread 20 being immediately adjacent the flange .18. The said thread has only a few, e.g., three or four, turns and is of coarse pitch.

The forward end of the tube is shaped to achieve an attractive appearance and to facilitate the gripping thereof by the fingers of a user during writing. By way of example, the forward end of the tube may include, moving from the male screw thread 20l toward the forward tip, a portion 22 which is concave in longitudinal section, an adjacent portion 24 having a protruding annular shoulder and an adjacent portion 26 of reduced diameter which is convex in longitudinal section.

A nib holder 28 constitutes the forward end of the cartridge 12, and said holder has a longitudinal through bore 30 formed therein, said bore being coaxial with the axis of the cartridge and running into the chamber. The holder has an enlarged head 31 and a rearwardly extending shank 32 which is fixed within a bore 33 in the forward portion of the tube 14. The holder is formed from plastic.

The rear end of the cartridge constitutes a generally cylindrical one-piece plastic plug 34, said plug closing the rear end of the chamber 16. The plug 34 includes at its forward end, a forwardly tapering head 35. Rearward of the head is a cylindrical stopper 36 which is fixedly secured within the rear end of the tube 14, as by force fitting, heat and pressure sealing, glucing or ultrasonic vibrational mating. The plug further includes an annular coaxial shoulder 38 adjacent to and rearward of the stopper 36. The shoulder is of larger diameter than the internal diameter of the tube so that the shoulder cannot enter the tube. The front of the shoulder abuts the rear edge of the tube and the outside diameter of the shoulder is optionally the same as but not larger than the outside diameter of the tube. A hexagonal (in transverse cross section) coaxial neck 40` is formed on the plug, rearward of the shoulder 38. A diagonal line running between diametrically opposed apices of the hexagonal neck is of a length the same as the diameter of the shoulder 38; that is, the outline of the neck 40 does not protrude beyond the outline of the shoulder. An external, i.e., male, coaxial screw thread 42 is formed rearward of the neck 40. Said thread has only a few turns and is of coarse pitch. The plug 34 has a cylindrical shank 43 extending rearwardly from the screw thread 42. The shank is coaxial with the remainder of the plug. The plug 34 has a rearward face 45 which is segmentally spherical and which, as will soon be evident, can be viewed by a user of the pen.

A cylindrical elongated wad `44 of ink-absorbent porous material is situated Within the chamber 16- and desirably lls a major portion of the chamber. The wad is suitably formed from cotton batting. An elonagted cylindrical porous nib 46 suitably formed from radially compressed nylon fibers is located in the bore 30, with the forward end of the nib 48 protruding axially from and being exposed externally of the nib holder 28. The nib at its front is formed into a tapering tip and the rearward end 50 of the nib extends into liquid transferring contact with the wad 44. A small radial pin 52 extends from the holder 28 radially into the nib 46 to secure the nib in place. The wad is saturated with a supply of ink and ink feeds from the wad to the nib and through the nib by capillary action. The ink is of the quick drying type.

The pen 10` of my invention further characteristically includes a hollow double open-ended barrel S4, optionally of circular internal and external cross section. The barrel ensheaths a major portion of the cartridge, said portion extending from the iiange 18 to adjacent the rear of the tube. The barrel has an internal diameter complementary to the external diameter of the rear portion 14a of the tube 14. The barrel and tube are so mutually shaped that the barrel can be telescoped forwardly over the rear end of the cartridge 12. For this purpose the interior of the barrel preferably is tapered, at least slightly, rearwardly. The external diameter of the barrel 54 desirably tapers from its forward end to its rearward end for a pleasant feel in the users hand. The barrel may be formed from metal, hard rubber or from opaque, translucent or transparent rigid plastic. Advertising matter or other indicia may be imprinted on the barrel directly or, as at A, on the cartridge where it is protected by and visible through a clear barrel. Moreoverm, the external diameter of the forward portion of the barrel is the same as the external diameter of the liange 18 so that the flange and the barrel fair smoothly into one another.

The barrel has an axial length which is approximately the same as the distance from the rear of the flange 18 to the rear of the neck 40 so that when the barrel is slipped forwardly onto the cartridge, its rear edge is immediately forward of the rear male screw thread 42. However, as will be seen, small variations in the length of the barrel are compensated for in the assembly of the pen.

The internal surface of the barrel at its rear end is formed into a radially inwardly protruding ange defining a hexagonal opening which is complementary to the congurations of the hexagonal neck 40 of the plug 34. The mating of the plug to the barrel at the neck prevents turning of the barrel with respect to the cartridge after these parts are telescoped. This is an optional feature of my invention.

A ferrule 56 ensheaths the rear end of the cartridge, that is, the plug 34. The ferrule is, in fact, in the fully assembled pen an extension of the barrel, although it is a separate unit. The ferrule 56 is hollow and double openended and an internal, i.e., female, screw thread 58 is formed on its forward interior surface to mesh with the screw thread 42. The ferrule threads over the plug 34 to a point at which the forward edge of the ferrule abuts the rear edge of the barrel 54. This action clamps the barrel under compression, on the forward end, between the flange 18 and, on the rearward end, the ferrule 56. If the barrel is perchance slightly shorter or longer, due to manufacturing tolerance, the ferrule is threaded onto the plug to, respectively, a larger or lesser degree to 'accommodate such variation, but always to a point at which the forward edge of the ferrule presses against the barrel. To insure that the ferrule can pass by the neck 40, the ferrule has a leading lip 57 with an internal diameter greater than the aforesaid diagonal ofthe neck.

The ferrule has at its forward end an external diameter which matches the external diameter 0f the rear end 0f the barrel so that these parts smoothly blend into one another. The ferrule has a rearwardly tapering configuration. The rear end of the ferrule 56 is open to expose the rear face 45 of the plug 34 to view.

The cartridge components, viz., the tube and the plug, are molded from a material of a color that matches and thus identities the color of the ink carried by the cartridge. The aforesaid color enables the user to pick a cartridge bearing the ink color he desires at a retail store and f-urther the colors of the peripheral surface of the flange 18 and the exposed rear face 45 identify the color of the ink carried by the cartridge, when the cartridge is assembled into the pen. The construction is such, as previously said, that the flange and the rear face are always exposed to view after the cartridge is assembled into the pen. Since these surface colors are permanent parts of the cartridge, the color of the ink is always known, regardless of the colors of the barrel, the cap or the ferrule.

The fiber-tip pen furt-her includes a removable cap 60 which is hollow and internally conical to fit over the forward end of the cartridge 12. The cap has an internal, i.e., female, screw thread 62 formed on its intern-al surface at the rearward end thereof. The internal screw thread 62 is matable with the external screw thread forward of the flange 18 and the cap can be screwed onto the cartridge until its rearward edge presses against said flange. The cap 60 at its rearward end has an external diameter which is the same as the external diameter of the ange 18 so that when the cap is on the pen, the cap blends smoothly into the ange and the barrel. The forward end of the cap is tapered. A pocket clip 64 is carried externally by the cap.

The cap 60 has formed in one piece therewith in its interior an annular sealing flange 66 which denes a passageway for the forward portion of the cartridge. The flange protrudes longitudinally rearwardly and provides a short cylindrical surface coaxial with the remainder of the cap 60. The flange 66 has a forward portion integral with the cap wall and a rearward free portion radially inward from the said wall of the cap. The flange is of sulciently thin section that it is llexible and resilient.

The flange mates with a circumferential zone on the forward portion of the cartridge, when the cap is screwed onto the remainder of the pen. Said zone is rearward of the usual air vent, subsequently described. The internal diameter of the flange in repose is somewhat, e.g., 0.005 inch, less than the external diameter of the mating forward portion of the cartridge and the cartridge tapers forwardly through said zone. Thus, as the cap is telesc'oped over the front portion of the cartridge, said front portion enters the passageway through the sealing flange and expands the flange radially outwardly. The flange is resilient and the return pressure of the llange presses the flange against the forward portion of the cartridge forming a circumferential seal between these components. This prevents ink from evaporating from the wad 44 through the nib 46 and the air vent. When the cap 60 is on the pen 10, the pen has a good looking tapering trim appearance.

An air vent is provided to admit ambient air under atmospheric pressure into and along the length of the chamber 16 to its rear end in back of the cartridge. Said vent includes several, eg., four, like equiangular radial slots formed in the cartridge, only the radial slot 68 being shown for clarity. The slot is formed in the rearwardly facing shoulder of the nib holder adjacent the abutment of the nib holder 28 and the forward end of the tube 14. Said slot is situated forwardly of thesealing flange 66 of the cap. Several, e.g., four, longitudinally elongated grooves run along the interior surface of the nib holder, each from the inner end of a different radial slot rearwardly to a relief 70 at the forward end of the chamber 16. Only one of the grooves 69 is illustrated.

An axially elongated groove 72 is formed in the external surface of the wad 44 and runs the length thereof. The groove 72 runs into a space 74 at the rear of the tube surrounding the tapered head 35 of the plug 36. Thus, the air vent constitutes the serially connected radial slots, grooves in the nib holder, relief, groove in the wad `and lastly the space around the plug. The air vent prevents the formation of a vacuum in the tube when ink flows therefrom.

The plastic of the cap 60 is suitably formed, e.g., by injection molding, from polyethylene or polypropylene, such material enabling the thin annular flange to llex. The barrel is suitably formed, e.g., by injection molding, from cellulose acetate butyrate. The tube is suitably formed, e.g., by injection molding, from medium impact polystyrene, the same being irmprevious to ink.

When the cap is removed, the forward portion of the cartridge, that is, the flange 18, the external screw thread 20, the concave portion 22, the shoulder portion 24 and the convex portion 26 form a part of the external surface of the pen and may be seen and gripped by a user. It will be appreciated that since a portion of the cartridge forms a part of the external surface of the pen, the internal chamber 16 and thus the wad 44 may be made relatively large. This increases the ink holding capacity of my pen which enables the same to be used for prolonged periods of time.

When it is desired to replace the cartridge 12 due to the cartridge having expended its ink supply, first the ferrule 56 is screwed olf the plug 34 and then the barrel I54 is slipped off of the cartridge. With a fresh cartridge in hand, the barrel is iirst slipped over the rear end of the cartridge toward theange and then the ferrule -56 is screwed onto the plug on the end of said fresh cartridge. Thereby, in a quick and easy manner, the pen has Ibeen reassembled With a substitute cartridge.

The liber-tip writing pen of the present construction is considerably more marketable than previous liber-tip pens which were of the throw-away type. These former pens had to be discarded once their ink supply was expended. Persons who used such pens were often dissatised because the entire unit had to be thrown away, leaving the feeling with these persons that they had purchased an item of only limited life. lOf necessity, such previous throw-away fiber-tip pens were of cheap construction. This was because their initial price had to be very low to compensate for the consumers awareness that he would have to discard the same. With the present invention, the barrel, ferrule and cap may be of high quality since these parts will be retained Iby the user when the cartridge is replaced. Moreover, the cartridge will be desirably sold at a price less than the price of the previous throw-away pens. A consumer buying the pen of the present invention will not mind paying a relatively high price because'he knows that he will retain a high quality pen and will be able to purchase replacement cartridges at a relatively low cost.

It is apparent that a pen manufacturer, using the cartridge of the present invention as a core, may assemble the pen with a barrel, ferrule and cap of almost any shape, form, material and color, as long as said components are formed internally to mate 'with the cartridge. Thus, a manufacture may market many styles of liber-tip pens, using my cartridge as a basic and standard part.

It thus will be seen that I have provided a fiber-tip writing pen with a replaceable ink-carrying cartridge which achieves the several objects of my invention and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention and as various changes might be made in the embodiment set forth, it is to be understood that all matter lherein described or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A replaceable cartridge liber-tip writing pen comprising:

(a) an elongated cartridge defining an elongated internal chamber,

(b) an ink-saturated porous wad situated within and filling a substantial portion of the chamber,

(c) a fiber nib protruding longitudinally from the forward end of the cartridge and having an interior portion in iluid contact with the wad,

(d) the cartridge having:

(i) a circular radially outwardly protruding `squat flange situated on the cartridge intermediate its ends, the flange forming a portion of the external surface of the pen and being exposed to view, said flange having opposite longitudinally facing surfaces,

(ii) a portion immediately forward of the -lange `with a male screw thread formed thereon, and

(iii) a plug integrally closing and rearwardly extending from the rear of the cartridge with a male screw thread formed on said rearwardly extending portion of said plug,

(e) a double open-ended barrel ensheathing the cartridge from the flange rearwardly to the plug while leaving the male screw t-hread protruding therefrom, lsaid barrel being removably telescoped over the rear of the cartridge and the plug with the forward end of the barrel pressed against one longitudinally facing surface of the `flange,

(f) a ferrule ensheathing the male screw thread at the rear of the cartridge and threadedly removably mated with said male screw thread, the front edge of the ferrule pressing against the rear edge of the barrel, and

(g) a cap covering the front of the cartridge and threadedly removably mated with the male screw thread forward of the flange, said cap being seated against the other longitudinally facing surface of the ange,

(h) removal of the cap exposing the portion of the cartridge forward of the flange, said portion then forming a portion of the external surface of the pen and then being grippable by the user during writing.

2. A writing pen as set forth in claim 1 further including mating means on the barrel and the cartridge, said means preventing realtive rotation between the barrel and the cartridge.

3. A writing pen as set forth in claim 2 wherein the mating means includes a noncircular mating surface on the barrel and a noncircular mating surface on the cartridge, said surfaces abutting to prevent relative rotation between the barrel and the cartridge.

4. A writing pen as set forth in claim 1 wherein the plug includes a hexagonal neck and the barrel includes an internal hexagonal portion complementary to and mated with the hexagonal neck, whereby rotation of the barrel with respect to the cartridge is prevented.

5. A writing pen as set forth in claim 1 wherein the cap adjacent the flange has an outside diameter, the ange has an outside diameter and the barrel adjacent the flange has an outside diameter, said diameters being of the `same size so that the pen with the cap thereon has a smoothly faired appearance.

6. A writing pen as set forth in claim 5 wherein the rear end of the barrel has an outside diameter and the forward end of the ferrule has an outside diameter, said diameters being of the same size so that the pen has a smoothly faired appearance.

7. A writing pen as set forth in claim 1 wherein an air vent is formed in the cartridge for passage of ambient air to the chamber, the cap has formed in one piece therewith and internally thereof an annular longitudinally rearwardly extending resilient flange spaced inwardly from the cap, said ange abutting the cartridge at a circumferential zone on the forward portion of the cartridge and rearwardly of the air vent, the internal diameter of the flange being less than the external diameter of the cartridge at said zone, the cartride tapering forwardly through said zone, the mating of the cap with the cartridge expanding the ange radially outwardly toward the barrel and the return pressure of the yflange against the cartridge forming a seal between the cap and the cartridge to inhibit evaporation of the ink through the nib and from the air lvent. i

References Cited UNITED STATES PATENTS 3,002,517 10/1961 Pitton 401--172 3,003,182 10/1961 Rosenthal 401-199 X 3,048,879 8/1962 4Rosenthal 401-199 3,087,464 4/ 1963 Wittne Bert et al. 401-251 X 3,154,873 11/1964 Shea 40--334 3,361,516 1/1968 Rigondaud 401-292 FOREIGN PATENTS 985,592 3/1951 France. 331,120 10/ 1935 Italy.

LAWRENCE CHARLES, Primary Examiner.

U.S. Cl. X.R. 401-202, 251 

